Well I have been watching some astronomy pictures, some of these were taken by 20,30,40D´s and 50mm 1.8 Lenses.
They looked pretty awesome,

^just an example I found.

I was wondering, what is the chance for a beginner to manage to take a picture like that?
I got a Manfrotto Tripod, so that shouldnt be a problem.
Also, I am using a 7D and a 24-70 2.8 L and a 70-200 2.8 L lens.
Would this equipment be of any use? Do I need a "modified" Dslr?

If someone could clear these things up a little, it would be very appreciated.

To me that looks like a "sandwich" of several long exposures stacked.
Beginner taken that, hmm, I would say slim, but if your are thorough and lucky, why not? ^^

To shorten and sum things up:First, just a DSLR and a lens does not weigh much, this is good, because the more weight the more beefy motorized tripod you need.
An EQ5 or equivalent would probably be enough, however HEQ5 would be the next step if a little more weight is added and even more thorough tracking is needed.
Second, tracking, this is done with a small refractor telescope, a star tracker camera and a laptop.
(An EQ5 can track without all this extra equipment, but not very accurate, not sure to what extent though, but I have heard 10-30 seconds.)
Third, making the tripod ready for the part of the hemisphere you are on, making sure that it's completely level and on a surface that is completely solid.
Fourth, weather and light pollution, one of em you might be able to get away from, but the other will control you completely.

Btw, I have a HEQ5, Celestron 10" Newtonian reflector and some TeleVue 1,25 lovely optics. I have only done pure visual stuff so far, no photography worth mentioning. A telescope like the one I have is way to heavy for my tripod, just as an example.

I was asking myself the same thing yesterday.
I want those celestial explosions and everything without a telescope.
However, all I'm gonna get is what I see by naked eye, right?
That's sad...
The fact that there is no Aurora Borealis here is even more sad...

I had a go at the same subject before, see here. I'm using a Celestron Nexstar 4SE which isn't the best for that as its focal length is a bit long, and here I'm zoomed right in on the central bright region. I think the 70-200 on a tracking mount would be interesting.

Depending on where you live, light pollution might be a hurdle. As I used the scope, I could get a cheap light pollution filter which helps a lot. With a lens, there is one that fits between the lens mount and mirror box I haven't tried.

Firstly you can use your camera and lenses for wide field AP. Having a guided mount will certainly be beneficial allowing longer exposures and thus more detailed revealed. (There are further discussions on digital noise but we can leave these for later.) You can get a mount such as an EQ5 which will RA track or an Astrotrac which is purpose built for cameras.

The second option is to buy a guided mount and scope and attached your camera direct to that (prime focus) in effect you are using the scope as a big lens. The latter can become very expensive very quickly.

I would suggest thinking about which route you want to go down and then let us know.

menorzinho: Actually when looking trough a telescope with your bare eyes you'll see...almost nothing. When bringing a newcomer is brought to a very dark location along with a very big telescope he/she will still say "That's all?".

The human eye just isn't sensitive enough to reveal much. Other than the very bright objects like open clusters and the biggest nebula/galaxies will reveal some detail. And that's at a dark site away from the cities. From this light polluted city I live in all I can see is the very center of the andromeda galaxy, the brightest part. And this is all without color as the night vision part of your eyes can't see any.

With photography (both analog and digital) you can expose for as long as it takes. You'll see infinitely more with a camera than without.

Symtex: Money yes. But don't forget knowledge in the field of optics, astronomy, DSLR's and image processing. A dark sky (no light pollution) without turbulent skies, the jet stream or moisture, which can be quite a few hours driving away. Then there's the things not even the professionals are in control of like clouds and other stuff in the atmosphere, satellites and even the glare of the moon drowning out objects. Oh and lots, LOTS of time and patience and (optionally) a wife who can put up with all the expenses and late nights/mornings.

It's also worth noting that there isn't a very large gap between the equipment used by amateurs and professionals, in fact they overlap slightly at the high end. It's a very wide spectrum all the way from a small ~4 inch refractor and/or a cheap DSLR to something like a 16 inch reflector+guidescope mounted on a purpose build pier with a purpose build camera outfitted with a very expensive CCD sensor which is connected to a laptop.

For every 100% increase in capabilities you'll see something like a 1000% increase in price as it gets more and more specialized. For example: A nice equatorial mount (like a HEQ5) will set you back at least 1000 dollars but if you want one that's better than that you'll need to spend around 10k from a more higher end range of choices.

To the OP; If you aren't discouraged by this then astro-photography is for you.